hello everybody from Greece.
A month ago i had the first to second and no way third to second gearbox problem in my F85 Fourtrack. Reading the solution here, i remove easily the transfer yesterday and i found the famous nut a little rusty and completely loose. The screw is OK but the nut is for the garbage...
I change the nut with -an almost the same- new from an unknown hub and i change also the 6307 bearing in the input end of the main shaft of the transfer (this one very close to the nut...)
After that everything is OK with the gearbox (it became smooth without noises)
The whole job took about six hours...
thank you very much for the detailed infos about my problem...
Panagis